Information recording medium cartridge having a pair of movable shutter members

ABSTRACT

A recording medium cartridge includes a disc, an inner rotor and a shutter in a shell. Torque is applied to the inner rotor by a coil spring to drive the shutter so as to maintain the closed state of an opening part provided in the shell. When the recording medium cartridge is inserted into a disc device, the inner rotor is rotated against the resilient force of the coil spring by a shutter opening mechanism provided in the disc recording and reproducing device. Thus, the shutter is moved to a position where the opening part provided in the shell is opened. When the cartridge is ejected from the disc device, the inner rotor is rotated by the resilient force of the coil spring to close the shutter.

TECHNICAL FIELD

The present invention relates to a recording medium cartridge includinga cartridge casing having upper and lower shells (upper and lowerhalves) in which a disc shaped information recording medium, such as anoptical disc, a magneto-optical disc, a magnetic disc, etc., an innerrotor and a shutter are accommodated, wherein the inner rotor is rotatedin one direction so that an opening part provided in at least one shellof the upper and lower shells of the cartridge casing is opened by theshutter. Particularly, the present invention relates to a recordingmedium cartridge in which the shutter can be easily and assuredly drivenfrom a position where a recording/reproducing opening part and a centralopening part are opened to a position where the recording/reproducingopening part and the central opening part are closed by using anextension coil spring or a compression coil spring shutter.

BACKGROUND ART

As shown in FIG. 30, a recording medium cartridge of a below-describedtype has been widely employed (for example, Japanese Patent ApplicationLaid-Open No. hei 2-162275) as a recording medium cartridge 101. Therecording medium cartridge 101 includes a disc 102, a shell (case) 103in which the disc 102 is accommodated so as to rotate freely, a shutter105 for opening and closing an opening part 104 for recording andreproducing data provided in the shell 103, and a shutter spring 106 forurging the shutter 105 to close the opening part 104. The shutter 105 islinearly moved relative to the shell 103 by the shutter spring 106 toopen and close the opening part 104 for recording and reproducing data.

In the recording medium cartridge, the shutter 105 is linearly movedrelative to the shell 103. Further, as shown in FIG. 31, a recordingmedium cartridge 201 of a type that a shutter 105 is rotated relative toa shell 103 to open and close an opening part 104 for recording andreproducing data has been developed (for example, Japanese Utility ModelApplication Laid-Open No. sho 61-57364).

In the recording medium cartridge 101 shown in FIG. 30, since theshutter 105 is moved linearly relative to the shell 103 to open andclose the opening part 104 for recording and reproducing data, theopening part 104 for recording and reproducing data can be opened andclosed with a small amount of movement. Accordingly, even when a torsioncoil spring is employed for the shutter spring 106, the shutter 105 canbe maintained assuredly in a closed state by the shutter spring 106.

On the contrary, in the recording medium cartridge 201 in which theshutter 105 is rotated relative to the shell 103 to open and close theopening part 104 for recording and reproducing data, when the springforce of a shutter spring 106 is exerted on the outer peripheral side ofthe shutter 105 to rotate the shutter 105 throughout a wide angle, thetorsion coil spring as the shutter spring 106 is brought into what iscalled a completely opened state, as shown in FIG. 31, so that aresiliency is weakened. Thus, the shutter 105 is hardly maintainedassuredly in a closed state.

The present invention provides a recording medium cartridge of a typethat a shutter is rotated relative to a shell to open and close anopening part for recording and reproducing data in which the shutter canmaintain assuredly the opening part for recording and reproducing datain a closed state.

DISCLOSURE OF THE INVENTION

The invention defined in claim 1 concerns a recording medium cartridgecomprising: a cartridge casing composed of upper and lower shells havingan information recording medium, an inner rotor and a shutteraccommodated therein, a recording/reproducing opening part for allowingone part of the information recording medium to diametrically face atleast one shell of the upper and lower shells of the cartridge casing;and a central opening part for driving the information recording medium.The inner rotor is rotated in one direction to drive the shutter andopen the recording/reproducing opening part and the central openingpart. The shutter is driven from a position where therecording/reproducing opening part and the central opening part areopened to a position where the recording/reproducing opening part andthe central opening part are closed by rotating the inner rotor to theother direction by an extension coil spring or a compression coilspring.

Thus, the shutter is driven to open the recording/reproducing openingpart and the central opening part by a shutter opening mechanismprovided in a disc recording and reproducing device for recording and/orreproducing data in the recording medium cartridge. The shutter issimply and assuredly driven from the position where therecording/reproducing opening part and the central opening part areopened to the position where the recording/reproducing opening part andthe central opening part are closed by rotating the inner rotor to theother direction by the extension coil spring or the compression coilspring. Further, the shutter can be kept closed by the resilient forceof the coil spring.

The invention defined in claim 2 concerns a recording medium cartridgeaccording to claim 1, wherein the extension coil spring or thecompression coil spring is arranged so as to be wound on the outerperipheral part of the inner rotor, one end part is engaged with theinner rotor and the other end part is engaged with the cartridge casing.

Thus, the shutter is driven to open the recording/reproducing openingpart and the central opening part by rotating the inner rotor againstthe resilient force of the extension coil spring or the compressionspring by the shutter opening mechanism provided in the disc recordingand reproducing device. The shutter is driven to close therecording/reproducing opening part and the central opening part byrotating the inner rotor under the resilient force of the extension coilspring or the compression coil spring accumulated by the rotation of theinner rotor.

The invention defined in claim 3 concerns a recording medium cartridgeaccording to claim 1, wherein the extension coil spring or thecompression coil spring has a wire diameter of 0.2 mm or smaller and acoil diameter of 1.5 mm or smaller.

Thus, the extension coil spring or the compression coil spring can bearranged in a narrow space between the shell and the inner rotor.

The invention defined in claim 4 concerns a recording medium cartridgeaccording to claim 1, wherein the extension coil spring or thecompression coil spring is formed in a curved form corresponding to thecurvature of the outer peripheral part of the inner rotor.

Thus, the extension coil spring or the compression coil spring is easilyattached to the outer peripheral part of the inner rotor.

An information recording medium cartridge defined in claim 5 concerns aninformation recording medium cartridge according to claim 1, whereinwhen the recording medium cartridge is inserted into a disc recordingand reproducing device, the inner rotor is rotated against the resilientforce of the coil spring by a shutter opening mechanism provided in thedisc recording and reproducing device to move a pair of shutter membersof the shutter to a second position where the opening parts provided inthe cartridge casing are opened.

Thus, after recording and reproducing operations are finished on therecording medium cartridge, when the recording medium cartridge isejected from the disc recording and reproducing device, the inner rotoris returned and rotated by the resilient force of the coil spring toreturn and move a pair of shutter members of the shutter to a firstposition where the opening parts provided in the cartridge casing areopened.

An information recording medium cartridge defined in claim 6 concerns aninformation recording medium cartridge according to claim 1, wherein anengaging part at one end of the coil spring is engaged with a bossshaped spring engaging part protruding on the inner surface of thecartridge casing and an end part of the spring engaging part is providedwith an engaging part slip preventing flange part.

Thus, the engaging part at one end of the coil spring is prevented fromslipping from the boss shaped spring engaging part by the engaging partslip preventing flange part.

An information recording medium cartridge defined in claim 7 concerns aninformation recording medium cartridge according to claim 1, wherein anengaging part at the other end of the coil spring is engaged with a hookshaped spring engaging part provided in a coil spring attaching part ofthe inner rotor.

Thus, the engaging part at the other end of the coil spring can beeasily and assuredly engaged with the inner rotor side.

An information recording medium cartridge defined in claim 8 concerns aninformation recording medium cartridge according to 1, wherein the coilspring attaching part is formed by recessing the end part of a ring sideof the outer peripheral surface of the inner rotor in an annular form sothat the outer peripheral part of the attached coil spring maintains anon-contact state with the cartridge casing.

Thus, the outer peripheral part of the coil spring is prevented fromprotruding from the outer peripheral surface of the ring part of theinner rotor to prevent the coil spring from coming into contact with(interfering with) the cartridge casing

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a recording medium cartridge viewedfrom an upper surface side.

FIG. 2 is a perspective view showing the recording medium cartridgeviewed from a lower surface side (a shutter closing state).

FIG. 3 is an exploded perspective view of FIG. 1.

FIG. 4 is an exploded perspective view of FIG. 2.

FIG. 5 is a perspective view showing the recording medium cartridgeviewed from a lower surface side (a shutter opening state).

FIG. 6 is a bottom view of main parts of the cartridge showing a statein which a shutter is closed from the lower surface side.

FIG. 7 is a bottom view of main parts of the cartridge showing a statein which the shutter is opened from the lower surface side.

FIG. 8 is a perspective view of a shutter spring.

FIG. 9 is an enlarged plan view of a shutter spring attaching part.

FIG. 10A is a perspective view of an engaging part (part A of FIG. 9) ofa shell side with one end of the shutter spring, and FIG. 10B is asectional view taken along a line C—C of FIG. 10A.

FIG. 11A is a perspective view of an engaging part (part B of FIG. 9) ofthe other end of the shutter spring with an inner rotor side, and FIG.11B is a sectional view taken along a line D—D of FIG. 11A.

FIG. 12 is a plan view of an inner surface side of an upper shell.

FIG. 13 is a plan view of an inner surface side of a lower shell.

FIG. 14 is a plan view showing a state in which the inner rotor isattached to the lower shell to align the opening parts of both themembers with each other.

FIG. 15 is a plan view showing a state in which the inner rotor isattached to the lower shell to displace the positions of the openingparts of both the members from each other.

FIG. 16 is a perspective view of a shutter member viewed from an uppersurface side.

FIG. 17 is a perspective view of the shutter member viewed from a lowersurface side.

FIG. 18 is a perspective view showing a state in which the shuttermember is attached to the inner rotor to open the opening parts.

FIG. 19 is a perspective view showing a state in which the shuttermember is attached to the inner rotor to close the opening parts.

FIG. 20 is a perspective view of a disc recording and reproducingdevice.

FIG. 21 shows an operational relationship between a cartridge casing anda shutter mechanism and is an explanatory view for showing a state inwhich opening parts are completely closed by the shutter member.

FIG. 22A is a sectional view showing a state in which the lift-upprotruding part of the inner rotor is mounted on the lift-up protrudingpart of the upper shell and FIG. 22B is a sectional view showing a statein which lift-up protruding part of the inner rotor is disengaged fromthe lift-up protruding pat of the upper shell.

FIG. 23 is an explanatory view showing a state in which the inner rotoris slightly rotated from the state shown in FIG. 21 so that a pair ofshutter members is slightly opened.

FIG. 24 is an explanatory view showing a state in which the inner rotoris further slightly rotated from the state shown in FIG. 23 so that thepair of shutter members is further slightly opened.

FIG. 25 is an explanatory view showing a state in which the inner rotoris further rotated from the state shown in FIG. 24 so that the pair ofshutter members is further opened.

FIG. 26 is an explanatory view showing a state in which the inner rotoris further rotated from the state shown in FIG. 25 so that the pair ofshutter members is further opened.

FIG. 27 is an explanatory view showing a state in which the inner rotoris further rotated from the state shown in FIG. 26 so that the pair ofshutter members is completely opened.

FIG. 28 is a perspective view of another embodiment of a shutter spring.

FIG. 29 is a sectional view showing another attaching example of ashutter spring.

FIG. 30 is a plan view of a conventional example.

FIG. 31 is a plan view of another conventional example.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the description of a recording medium cartridge of the presentinvention is classified into the items of (1) schematic structure ofrecording medium cartridge and structure of shutter spring, (2)structure of cartridge casing, (3) structure of information recordingmedium, (4) structure of inner rotor, (5) structure of shutter, (6)operation and (7) other embodiments. The items will be described inorder.

(1) Schematic Structure of Recording Medium Cartridge and Structure ofShutter Spring

FIG. 1 is a perspective view showing a recording medium cartridge viewedfrom an upper surface side. FIG. 2 is a perspective view showing therecording medium cartridge viewed from a lower surface side. FIG. 3 isan exploded perspective view of FIG. 1. FIG. 4 is an explodedperspective view of FIG. 2. FIG. 5 is a perspective view showing therecording medium cartridge in a shutter opening state viewed from alower surface side.

As shown in FIGS. 1 to 5, a recording medium cartridge 1 includes aninformation recording medium 3, an inner rotor 4 and a shutter 5 thatare accommodated in a cartridge casing 2. An opening part 6 provided inthe cartridge casing (shell) 2 is opened and closed by the shutter 5.The shutter 5 is driven to open and close by rotating the inner rotor 4.

Torque is applied to the inner rotor 4 by a shutter spring 7 (referredto hereinafter as a coil spring).

The coil spring 7 rotates the inner rotor 4 to move the shutter 5composed of a pair of shutter members 5 a and 5 b to a first position atwhich the opening part 6 provided in the cartridge casing 2 is closed,as shown in FIG. 6. Then, when the recording medium cartridge 1 isinserted into a disc recording and reproducing device described below,the inner rotor 4 is rotated against the resilient force of the coilspring 7 by a shutter opening mechanism provided in the disc recordingand reproducing device. Thus, the pair of shutter members 5 a and 5 b ofthe shutter 5 is moved to a second position at which the opening part 6provided in the cartridge casing 2 is opened, as shown in FIG. 7.

As shown in FIG. 8, as the coil spring 7, an extension coil springhaving a wire diameter of 0.2 mm or smaller and a coil diameter of 1.5mm or smaller is used. The coil spring is formed in a curved shapecorresponding to the curvature of the outer peripheral part of the innerrotor 4. The coil spring has ring shaped engaging parts 7 a and 7 b atboth ends in the direction of length.

As shown in FIG. 9, the coil spring 7 is arranged so as to be wound onthe outer peripheral part of the inner rotor 4. The engaging part 7 a atone end is engaged with the cartridge casing 2 side. The engaging part 7b at the other end is engaged with the inner rotor 4.

As shown in FIG. 10, the engaging part 7 a at one end of the coil spring7 is engaged with a boss shaped spring engaging part 8 protruding on theinner surface of the cartridge casing 2. The end part of the springengaging part 8 is provided with an engaging part slip preventing flangepart 8 a.

Further, as shown in FIG. 11, the engaging part 7 b at the other end ofthe coil spring 7 is engaged with a hook shaped spring engaging part 9provided in a coil spring attaching part 4 a of the inner rotor 4.

The coil spring attaching part 4 a is formed by recessing the end partof a ring part 41 side on the outer peripheral surface 4 b of the innerrotor 4 in an annular form. When the coil spring 7 is attached to thecoil spring attaching part, the outer peripheral part 7 a of the coilspring 7 is prevented from protruding from the outer peripheral surface4 b of the ring part 41 of the inner rotor 4 to come into contact withthe cartridge casing 2 side.

(2) Structure of Cartridge Casing

As shown in FIG. 1, the cartridge casing 2 is formed by butting theperipheral surfaces 21 a and 22 a of upper and lower shells 21 and 22 oneach other.

As shown in FIG. 12, the upper shell 21 is formed with a substantiallysquare shaped thin tray member having a circular arc shaped frontsurface side. A peripheral wall 21 a is provided in its outer peripheraledge part.

The peripheral wall 21 a includes a front edge part 21 b, a pair of sideedge parts 21 c and 21 d and a rear edge part 21 e. On the central partof the rear edge part 21 e, a positioning recessed part 21 f forpositioning relative to the lower shell 22 is provided.

Inside the peripheral wall 21 a, specifically, in the corner part of thefront edge part 21 b and one side edge part 21 c, the corner part of oneside edge part 21 c and the rear edge part 21 e, and the corner part ofthe rear edge part 21 e and the other side edge part 21 d, respectively,circular arc shaped ribs 14 are provided.

Inside the circular arc shaped ribs 14, a ring shaped rib 15 isprovided. Inside the ring shaped rib 15, an accommodating part 16 forthe disc 3 is provided.

Outside the ring shaped rib 15, a ring shaped recessed part 17 to whichthe end of the ring part of the inner rotor 4 is fitted is provided, asspecifically described later. At symmetrical positions in upper andlower parts on the bottom surface of the ring shaped recessed part 17(positions in which a phase is shifted by 180°), lift-up protrudingparts 18 are provided for moving the inner rotor 4 so as to be separatedfrom the lower shell 22. The lift-up protruding parts 18 are mounted onlift-up protruding parts 46 of the inner rotor side provided on the endface of the ring part 41 of the inner rotor 4. Thus, the inner rotor 4is moved so as to be separated from the upper shell 21.

As shown in FIG. 13, the lower shell 22 is formed with a substantiallysquare shaped thin dish member having a circular arc shaped frontsurface side like the upper shell 21. A peripheral wall 22 a is providedon its outer peripheral edge part.

The peripheral wall 22 a includes a front edge part 22 b, a pair of sideedge parts 22 c and 22 d and a rear edge part 22 e. On the central partof the rear edge part 22 e, a positioning protruding part 22 f forpositioning relative to the upper shell 21 is provided.

Inside the peripheral wall 22 a, specifically, in the corner part of thefront edge part 22 b and one side edge part 22 c, the corner part of oneside edge part 22 c and the rear edge part 22 e, and the corner part ofthe rear edge part 22 e and the other side edge part 22 d, respectively,circular arc shaped ribs 19 are provided.

Inside the circular arc shaped ribs 19 of the lower shell 22, anaccommodating part for accommodating substantially half the thickness ofthe inner rotor 4 and a pair of shutters 5 is provided.

The upper and lower shells 21 and 22 are superposed on each other whilethe positioning protruding part 22 f is fitted to the positioningrecessed part 21 f and the peripheral walls 21 a and 22 a are butted oneach other.

On the lower shell 22, the opening part 6 is provided from the centralpart to the front edge part 22 b. The opening part 6 includes arecording/reproducing opening part 6 a for allowing a turn table of adisc rotating and driving mechanism and the optical head of an opticalpick-up device to face the information recording medium 3 and a centralopening part 6 b for allowing the turn table of the disc rotating anddriving mechanism to face information recording medium 3.

As shown in FIG. 2, at the substantially central parts of one side edgeparts 21 d and 22 d of the upper and lower shells 21 and 22, an openingwindow 30 for exposing a part of a gear 43 on the outer peripheralsurface of the inner rotor 4 is provided. The opening window 30 isformed by an upper shell side cut-out part 30 a provided in the uppershell 21 and a lower shell side cut-out part 30 b provided in the lowershell 22. Further, on the one side edge parts 21 c and 22 c of the upperand lower shells 21 and 22, guide grooves 31 extend forward and backwardalong connected surfaces. The guide grooves 31 are provided for thepurpose of preventing an erroneous insert when the recording mediumcartridge 1 is mounted on the disc recording and reproducing device. Theguide grooves 31 communicate with the opening window 30.

As shown in FIG. 3, in the corner part of the front edge part 22 b ofthe lower shell 22 and one side edge part 22 d, a lock memberaccommodating part 33 in which a lock member 32 is accommodated tofreely rotate is provided. The lock member accommodating part 33communicates with an accommodating part for the inner rotor of the lowershell 22 or the like and communicates with the guide grooves 31 throughan opening hole 34 provided in one side edge part 22 d. Further, in thelock member accommodating part 33 of the lower shell 22, a support shaft35 for supporting the lock member 32 so as to freely rotate protrudes tothe upper shell 21 side.

The lock member 32 is formed with a lever shaped member fitted to thesupport shaft 35 so as to freely rotate and swing in the direction of aplane. A stopper part 36 having a plurality of teeth is provided at oneend in the longitudinal direction of the lock member 32. An operatingpart 37 is provided at the other end in the longitudinal direction ofthe lock member 32. Further, the lock member 32 is provided integrallywith a spring piece 38 protruding in the same direction so as to beopposed to the stopper part 36.

The lock member 32 is fitted to the support shaft 35 while the stopperpart 36 is directed to the accommodating part for the inner rotor or thelike and the spring piece 38 abuts on the inner surface of the frontedge part 22 b. The stopper part 36 is urged toward the accommodatingpart for the inner rotor or the like by the resilient force of thespring piece 38 and the operating part 37 passes through the openinghole 34 from inside and protrudes into the guide grooves 31. Further, asshown in FIG. 3, to an erroneous erase preventing member attaching part91 provided in the corner part of the one side edge part 22 c and therear edge part 22 e of the lower shell 22, an erroneous erase preventingmember 92 is attached for preventing information recorded on therecording medium, such as an optical disc, from being erroneouslyerased.

(3) Structure of Information Recording Medium

As the information recording medium 3, a ROM optical disc exclusivelyused for reproducing on which a music signal as audio information or avideo signal as video information and various kinds of informationsignals such as music signals are previously recorded, or a write-onceoptical disc on which an information signal such as audio information orvideo information can be recorded only once, or a rewritable opticaldisc capable of repeatedly recording information many times has beenknown. In this embodiment, the rewritable optical disc (refer aninformation recording medium simply to as an optical disc, hereinafter)is used.

As shown in FIG. 3, the optical disc 3 is made of a thin disc shapedrecording member having a center hole 3 a at a central part.

The optical disc 3 is chucked on the turn table of a disc recording andreproducing device by a chucking plate 11 attached to the inner surfaceof the upper shell 21 by a chucking plate pressing member 10. Thus, theoptical disc is integrally formed in the rotating direction and rotatedat a prescribed speed (for instance, a constant angular velocity foreach turn: ZCAV).

On one surface of the optical disc 3, an information recording area 29 aopposed to the optical head of the optical pick-up device incorporatedin the recording and reproducing device and capable of recordinginformation and a non-recording area 29 b incapable of recordinginformation are provided. The non-recording area 29 b includes an insidenon-recording area 29 b provided with a prescribed width outside thecenter hole 3 a in the central part of the optical disc 3 and an outsidenon-recording area 29 b provided with a prescribed width on the outerperipheral edge of the optical disc 3. The information recording area 29a is provided between the inside and outside non-recording areas 29 band 29 b.

The optical disc 3 is accommodated in the ring part 41 of thebelow-described inner rotor 4 so as to rotate freely. As the material ofa substrate of the optical disc 3, a synthetic resin, such aspolycarbonate (PC), polymethacrylate (PMMA), is preferable. However, itis to be understood that other synthetic resins may be used and variouskinds of materials such as a glass material, aluminum alloy, etc. may beused except the synthetic resin.

The information recording medium is not limited to the optical disc. Theinformation recording medium may be applied to a magnetic disc in whicha magnetic thin film layer is formed on the surface of a thin disc tostore information in accordance with the magnetized condition of aspecific position, or a magneto-optical disc in which an optical headand a magnetic head are used on a similarly formed magnetic thin filmlayer to write or read information and other recording media.

(4) Structure of Inner Rotor

As shown in FIG. 3, the inner rotor 4 includes a flat surface part 40made of a disc shaped thin member and the ring part 41 providedcontinuously to the outer peripheral edge of the flat surface part 40.On the flat surface part 40 of the inner rotor 4, an opening part 42 isformed. The opening part 42, like the opening part 6 of the lower shell22, includes a recording/reproducing opening part 42 a for allowing theturn table of the disc rotating and driving mechanism and the opticalhead of the optical pick-up device to face the information recordingmedium 3 and a central opening part 42 b for allowing the turn table ofthe disc rotating and driving mechanism to face the informationrecording medium 3.

As shown in FIG. 4, the ring part 41 is formed in a cylindrical shapehaving a diameter slightly larger than the outside diameter of the ringshaped rib 15 provided in the inner surface of the upper shell 21. Thering part 41 is fitted to the outer periphery of the ring shaped rib 15so as to freely rotate and the end part thereof is inserted into thering shaped recessed part 17 provided outside the ring shaped rib 15.

On the outer peripheral surface of the ring part 41, a gear part 43having many teeth over a prescribed range in the circumference directionis provided. The gear part 43 is set to have an angle range a littlelarger than the rotating angle of the inner rotor 4. That is, as shownin FIG. 15, when the opening part 42 of the inner rotor 4 is inclined toa maximum relative to the opening part 6 of the lower shell 22 so thatthe pair of shutter members 5 a and 5 b are completely closed asdescribed below, an end of the gear part 43 in the circumferencedirection is located (exposed) at one end of the opening window 30. Aprotrusion engaging recessed part 44 provided in a stopper part 44 adescribed below is located (exposed) at the central part of the openingwindow 30. As shown in FIG. 14, when the inner rotor 4 is rotated by aprescribed angle so that the opening part 42 is superposed on theopening part 6 and the one pair of shutter members 5 a and 5 b arecompletely opened, the other end of the gear part 43 in thecircumference direction is located (exposed) in the opening window 30.

On both the sides of the gear part 43 of the inner rotor 4, stopperparts 44 a and 44 b for controlling an amount of rotation and movementof the inner rotor 4 are provided to protrude outward in the radialdirection.

As described above, since the gear part 43 and the stopper parts 44 aand 44 b protrude outside the outer peripheral surface of the ring part41, clearance grooves 45 a and 45 b are respectively provided on thecorresponding parts of the upper shell 21 and the lower shell 22. Thus,contact with the stopper parts 44 a and 44 b is avoided to permit thestoppers to pass.

As shown in FIG. 14, when the opening part 42 of the inner rotor 4 issuperposed on the opening part 6 of the lower shell 22, one end part ofthe stopper part 44 a is engaged with a stopper engaging part 45 cprovided in one end part of the clearance groove 45 a to prevent thefurther rotation of the inner rotor 4. Further, as shown in FIG. 15,when the opening part 42 of the inner rotor 4 is inclined to a maximumrelative to the opening part 6 of the lower shell 22, one end part ofthe stopper part 44 b is engaged with a stopper engaging part 45 dprovided at one end part of the opening part 6 to prevent the furtherrotation of the inner rotor 4.

On the end face of the ring part 41, lift-up protruding parts 46 areprovided at two positions in the circumference direction. While theopening part 42 of the inner rotor 4 is inclined to a maximum relativeto the opening part 6 of the lower shell 22, as shown in FIG. 15, thelift-up protruding parts 46 of the inner rotor 4 side are mounted onlift-up protruding parts 18 provided in the ring shaped recessed parts17 of the upper shell 21, as shown in FIG. 22(A). Further, on a surfaceopposite to the ring part 41 of the flat surface part 40 of the innerrotor 4, a pair of support shafts 49 and 49 for supporting the pair ofshutter members 5 a and 5 b so as to freely rotate in the direction of aplane, as shown in FIG. 4, are provided. The pair of support shafts 49and 49 are respectively point-symmetrically provided on the opening part42 as a center. Further, in the vicinity of the pair of support shafts49 and 49, fitting releasing protruding parts 48 and 48, which havetrapezoidal forms and substantially the same height as that of asubstantially H-shaped ribbed protruding part 12 a provided in the lowershell 22, are provided. These fitting releasing protruding parts 48 and48 serve to pull out the ribbed protruding part 12 a from a grooveshaped recessed part 12 b when the shutter members 5 a and 5 b move fromthe position shown in FIG. 15 (first position) where the opening 6 isclosed to the position shown in FIG. 14 (second position) where theopening part 6 is opened.

The trapezoidal fitting releasing protruding parts 48 and 48 are locatedin the side parts of second and fourth height parts 12 e and 12 gprovided in the end parts of the substantially H-shaped ribbedprotruding part 12 a provided in the lower shell 22 in the positionshown in FIG. 15.

(5) Structure of Shutter

As shown in FIGS. 16 and 17, the shutter 5 is composed of a pair ofshutter members 5 a and 5 b that are formed in the same shape and size.The pair of shutter members 5 a and 5 b is made of a plate member havingsubstantially the same thickness as the height of the first to thefourth height parts 12 d to 12 g (see FIG. 13) of the substantiallyH-shaped ribbed protruding part 12 a provided in the lower shell 22.

On the substantially central parts of the side lines of the pair ofshutter members 5 a and 5 b, step parts 50 are formed with prescribedlengths in the directions perpendicular to the side lines. On both thesides of step parts 50, protruding side connecting parts 50 a andrecessed side connecting parts 50 b are formed through the step parts50. On the connecting parts 50 a and 50 b of the shutter members 5 a and5 b, roof parts 51 a and 51 b are respectively protruded in thedirections perpendicular to the extending directions of the side lines.Thus, in the pair of the shutter members 5 a and 5 b, the end faces ofthe protruding side connecting parts 50 a are respectively opposed tothe end faces of the recessed side connecting parts 50 b. Thus, the roofparts 51 a of the protruding side connecting parts 50 a are respectivelysuperposed on the roof parts 51 b of the recessed side connecting parts50 b. In shaft attaching parts 50 c in the end parts of the protrudingside connecting parts 50 b on the side lines of the shutter members 5 aand 5 b, shaft receiving holes 52 are respectively formed.

In the end parts of the recessed side connecting parts 50 b on the sidelines of the shutter members 5 a and 5 b, cut-out parts 50 d arerespectively provided for introducing the second height part 12 e or thefourth height part 12 g provided at the end part of the substantiallyH-shaped ribbed protruding part 12 a of the lower shell 22.

The support shafts 49 on the flat surface part 40 of the inner rotor 4are fitted to the shaft receiving holes 52 so that the shutter members 5a and 5 b are respectively attached to the flat surface part 40 of theinner rotor 4 so as to rotate freely. At this time, the pair of shuttermembers 5 a and 5 b are attached with their side lines opposed to eachother. As a result, as shown in FIG. 18, when the pair of shuttermembers 5 a and 5 b are rotated so that they are separated outward fromeach other, the shutter members 5 a and 5 b are respectively mounted soas to be superposed on both sides of the opening part 42 of the innerrotor 4 by sandwiching the opening part 42 in between the shuttermembers. On the other hand, the pair of shutter members 5 a and 5 b arerespectively rotated inward so that the connecting parts 50 arespectively abut on the connecting parts 50 b. Thus, as shown in FIG.19, the pair of shutter members 5 a and 5 b closes the central part ofthe opening part 42.

Further, as shown in FIGS. 16 to 19, slots 53 (opening and closinggrooves) for opening and closing the shutter members 5 a and 5 b arerespectively provided in the recessed side connecting parts 50 b of theshutter members 5 a and 5 b. The slots 53 respectively extend in theradial direction on the shaft receiving holes 52 of the shutter members5 a and 5 b on which they are provided. In the slots 53, boss shapedprotruding parts 20 of the lower shell 22 are engaged to slide freely.Further, in end parts outside the slots 53 respectively, elastic pieces54 formed by cutting the peripheries thereof and recessed parts 53 a forreleasing the boss shaped protruding parts 20 are provided. In thecircular arc side edges of the shutter members 5 a and 5 b, closingprotruding pieces 55 are provided.

As shown in FIG. 22, while the shutter is closed, the protruding piece55 of the shutter member 5 a abuts on the first height part 12 d of thelower shell 22 and the protruding piece 55 of the shutter member 5 babuts on the third height part 12 f of the lower shell 22. Thus, thespace between them is closed.

Further, as shown in FIGS. 18 and 19, on the sliding contact surfaces ofthe shutter members 5 a and 5 b with the lower shell 22, groove shapedrecessed parts 12 b are provided, which are engaged with thesubstantially H shaped and ribbed protruding parts 12 a to form dustpreventing parts. When the shutter members 5 a and 5 b close the openingpart 42, the ribbed protruding parts 12 a of the lower shell 22 arefitted to the groove shaped recessed parts 12 b.

As the material of the shutter members 5 a and 5 b, for instance,synthetic resins, such as an ABS resin (acrylonitrile-Butadiene-Styreneresin), HIPS (high impact polystyrene), POM (polyacetal), etc., areemployed. Further, materials of a type having sliding characteristicsare preferable. However, it is to be understood that other syntheticresins may be applied, and other metal materials such as aluminum alloy,stainless steel, etc., may be employed.

(6) Operation of Recording Medium Cartridge

Now, the operation of the recording medium cartridge as well as thestructure of the disc recording and reproducing device will bedescribed. The disc recording and reproducing device 60 comprises, asshown in FIG. 20, an outer package case 61 made of a hollow casing and arecording and reproducing device main body (illustration is omitted)accommodated in the outer package case 61 or the like. The outer packagecase 61 includes a case main body 62 in which an upper surface and afront surface are opened, a case cover body 63 detachably attached to anupper part so as to close the upper surface of the case main body 62 anda front surface panel 64 detachably attached to a front part so as toclose the front surfaces of the case main body 62 and the case coverbody 63.

Leg members 62 a protruding downward are provided at four parts of thecase main body 62. The disc recording and reproducing device 60 issupported by these leg members 62 a. The front surface panel 64 is madeof a plate shaped member with a long breadth and a cartridge entry port65 with a long breadth is provided above the front surface panel. Thecartridge entry port 65 is formed to a size substantially the same asthat of a front surface side of the recording medium cartridge 1. Thecartridge entry port 65 is ordinarily closed by an opening and closingdoor 66 disposed inside the cartridge entry port.

The opening and closing door 66 is pressed by the front part of therecording medium cartridge 1 and inserted to a prescribed position.Thus, the recording medium cartridge 1 is automatically taken in by aloading mechanism not shown in the drawing. Then, the recording mediumcartridge 1 conveyed by the loading mechanism is positioned and fixed toa prescribed position in the disc recording and reproducing device 60.At the same time, or before or after the above-described operation, theshutter 5 is operated by a shutter opening and closing mechanismprovided in the disc recording and reproducing device 60 to open theopening parts 6 and 42.

Specifically, when the recording medium cartridge 1 is inserted to theprescribed position, as shown in FIG. 21, a rack rod 70 of the shutteropening and closing mechanism incorporated in the disc recording andreproducing device 60 enters the guide groove 31 provided in one sidesurface part of the recording medium cartridge 1. Thus, the operatingpart 37 of the lock member 32 protruding into the guide groove 31 ispressed into the lock member accommodating part 33 by the pressing forceof the rack rod 70 against the resilient force of the spring piece 38.Thus, the locked state of the inner rotor 4 by the lock member 32 isreleased. A rotating operation protrusion 70 c provided in the rack rod70 through an elastic piece 70 b is engaged with the protrusion engagingrecessed part 44 provided in the inner rotor 4 to rotate the inner rotor4. Further, the rack rod 70 relatively advances, so that the end of agear part 70 a thereof is engaged with the gear part 43 of the innerrotor 4.

The gear part 43 engages with the gear part 70 a of the rack rod 70 torotate the inner rotor 4 depending on the amount of movement of the rackrod 70. The coil spring 7 is expanded by the rotation of the inner rotor4 so that the resilient force is accumulated.

FIG. 21 shows a state before the gear part 70 a of the rack rod 70engages with the gear part 43 of the inner rotor 4. Under this state,the protruding side connecting parts 50 a and the recessed sideconnecting parts 50 b of the pair of shutter members 5 a and 5 b abut oneach other and come into tight contact with each other. At this time,since the opening part 42 of the inner rotor 4 is inclined relative tothe opening part 6 of the lower shell 22, only the central part in whichboth the opening parts 6 and 42 are superposed one upon another isopened; however, the opening parts are closed by the pair of the shuttermembers 5 a and 5 b. Accordingly, there is no fear that dust may enterthe disc accommodating part from the superposed part of the openingparts 6 and 42.

In parts on which the opening part 6 comes near to the opening part 42at an acute angle, the shaft attaching parts 50 c of the pair of shuttermembers 5 a and 5 b are provided. The shaft attaching parts 50 c arelocated inside the second and fourth height parts 12 e and 12 g of theribbed protruding part 12 a to eliminate the space. Further, the closingprotruding pieces 55 are provided inside the first and third heightparts 12 d and 12 f to eliminate the space. Further, the slots 53provided in the pair of shutter members 5 a and 5 b are closed by thelower shell 22 on which the pair of the shutter members 5 a and 5 b issuperposed. Still further, as shown in FIG. 21, the substantiallyH-shaped and ribbed protruding part 12 a provided in the lower shell 22so as to surround the opening part 6 is fitted to the groove shapedrecessed parts 12 b provided in the shutter members 5 a and 5 b to forma crank shaped dust preventing part. Thus, dust is prevented fromentering the disc accommodating part through the opening parts 6 and 42.

From this state, when the rack rod 70 enters the guide groove 31corresponding to the inserting operation of the recording mediumcartridge 1 and the engagement of the gear part 70 a with the gear part43 of the inner rotor 4 is started, the inner rotor 4 is rotatedclockwise. In this case, under an initial state that the rotatingoperation of the inner rotor 4 is started, as shown in FIG. 21 and FIG.22(A), the lift-up protruding parts 46 of the inner rotor 4 are mountedon the lift-up protruding parts 18 of the upper shell 21 to hold thepair of the shutter members 5 a and 5 b by the inner rotor 4. Therefore,the rotating operation of the inner rotor 4 needs a relatively largeforce. The inner rotor 4 is rotated against a large frictional force dueto the mount-up operation of both the lift-up protruding parts 18 and46, so that the lift-up protruding parts 18 and 46 are disengaged fromeach other, as shown in FIG. 22(B), to remove the frictional force.Consequently, the subsequent rotating operation of the inner rotor 4 iscarried out extremely lightly and smoothly.

The rotation of the inner rotor 4 allows the trapezoidal fittingreleasing protruding parts 48 and 48 provided on the bottom surface ofthe inner rotor 4 to be mounted on the first and third height parts 12 dand 12 f of the ribbed protruding part 12 a of the lower shell 22. Thus,the inner rotor 4 is lifted relative to the lower shell 22 and theshutter members 5 a and 5 b are also lifted to pull out the grooveshaped recessed parts 12 b from the ribbed shaped protruding part 12 a.

At this time, the shaft receiving holes 52 of the shutter members 5 aand 5 b are likewise rotated by the rotation of the inner rotor 4. Onthe other hand, in the slots 53 provided in the other end sides, theboss shaped protruding parts 20 and 20 of the lower shell 22 arerespectively engaged to slide freely.

The pair of the boss shaped protruding parts 20 and 20 are provided inthe lower shell 22 and do not move. On the other hand, the slots 53 areextended in the direction S for connecting the shaft receiving holes 52to the boss shaped protruding parts 20 so that the slots can moverelative to the boss shaped protruding parts 20 and 20 following therotation of the shutter member 5 a and 5 b. Thus, the boss shapedprotruding parts 20 and 20 move relatively in the slots 53 toward theshaft receiving holes 52 depending on the amount of rotation of theshutter members 5 a and 5 b. Accordingly, in each of the shutter members5 a and 5 b, the shaft receiving hole 52 moves to the corresponding bossshaped protruding part 20. As a result, from a state shown in FIG. 23,the shutter members 5 a and 5 b respectively move to both the side partsof the opening part 42 of the inner rotor 4, as shown in FIG. 27, viastates shown in FIGS. 24, 25 and 26. Thus, the upper and lower openingparts 6 and 42 are completely opened. Accordingly, a part of the opticaldisc 3 accommodated in the disc accommodating part is exposed by theopening parts 6 and 42. Then, the information signal is reproduced orrecorded by the recording and reproducing device main body 62.

After the information signal is reproduced or recorded, a cartridgeejection button (not shown) provided in the disc recording andreproducing device 60 is operated to eject the recording mediumcartridge 1 from the disc recording and reproducing device 60.

When the recording medium cartridge 1 is ejected, the inner rotor 4 isrotated in the direction reverse to that upon inserting the cartridge 1into the disc recording and reproducing device 60 by the accumulatedresilient force of the coil spring 7 to automatically close the shutter5. Accordingly, upon ejecting the recording medium cartridge 1, the gearpart 70 a of the rack rod 70 of the shutter opening and closingmechanism of the disc recording and reproducing device 60 does not needto be engaged with the gear part 43 of the inner rotor 4 to rotate theinner rotor 4. Therefore, the ejecting operation of the recording mediumcartridge 1 can be carried out simply and rapidly and abrasion of thegear part 43 of the inner rotor 4 can be prevented.

(7) Other Embodiments

In the above-described embodiment, although an example in which acircular arc shaped extension coil spring is used as the coil spring 7is described, the coil spring 7 may be a straight line shaped spring, asshown in FIG. 28. Further, the coil spring 7 may not be the extensioncoil spring and may be a compression coil spring. Further, in theabove-described embodiment, as shown in FIG. 11, the coil springattaching part 4 a is formed by recessing the end part of the flatsurface part 40 on the outer peripheral surface 4 b of the rib part 41of the inner rotor 4 in an annular form, and when the coil spring 7 isattached to the coil spring attaching part, the outer peripheral part 7a of the coil spring 7 is prevented from protruding from the outerperipheral surface 4 b of the rib part 41 of the inner rotor 4 tointerfere with the cartridge casing 2. However, as shown in FIG. 29, aspace G between the inner rotor 4 and the cartridge casing 2 may beadequately provided so that the outer peripheral part 7 a of the coilspring 7 does not come into contact with the inner surface of thecartridge casing 2.

INDUSTRIAL APPLICABILITY

The present invention can be widely applied to not only optical disccartridges but also to magnetic disc cartridges and magneto-optical disccartridges for CD, etc.

1. A recording medium cartridge comprising: a cartridge casing composedof upper and lower shells having an information recording medium, aninner rotor and a shutter accommodated therein and operably connected tothe inner rotor, the shutter having a pair of movable shutter memberscontacting each other in a closed position and disposed apart from oneanother in an opened position, a recording/reproducing opening part forallowing one part of the information recording medium to diametricallyface at least one shell of the upper and lower shells of the cartridgecasing; and a central opening part for driving the information recordingmedium, the inner rotor being rotated in one direction to drive theshutter and open the recording/reproducing opening part and the centralopening part, wherein the shutter is driven from a position where therecording/reproducing opening part and the central opening part areopened and the pair of shutter members are in the opened position to aposition where the recording/reproducing opening part and the centralopening part are closed and the pair of shutter members are in a closedposition by returning and rotating the inner rotor to the otherdirection by an extension coil spring or a compression coil spring. 2.The recording medium cartridge according to claim 1, wherein theextension coil spring or the compression coil spring is arranged so asto be wound on the outer peripheral part of the inner rotor, one endpart is engaged with the inner rotor and the other end part is engagedwith the cartridge casing.
 3. The recording medium cartridge accordingto claim 1, wherein the extension coil spring or the compression coilspring has a wire diameter of no greater than 0.2 mm and a coil diameterof no greater than 1.5 mm.
 4. The recording medium cartridge accordingto claim 1, wherein the extension coil spring or the compression coilspring is formed in a curved form corresponding to the curvature of theouter peripheral part of the inner rotor.
 5. The recording mediumcartridge according to claim 1, wherein when the recording mediumcartridge is inserted into a disc recording and reproducing device, theinner rotor is rotated against the resilient force of the coil spring bya shutter opening mechanism provided in the disc recording andreproducing device to move the pair of shutter members of the shutter tothe opened position where the opening parts provided in the cartridgecasing are opened.
 6. The recording medium cartridge according to claim1, wherein the coil spring attaching part is formed by recessing the endpart of a ring side of the outer peripheral surface of the inner rotorin an annular form so that the outer peripheral part of the attachedcoil spring maintains a non-contact state with the cartridge casing. 7.A recording medium cartridge comprising: a cartridge casing composed ofupper and lower shells having an information recording medium, an innerrotor and a shutter accommodated therein, a recording/reproducingopening part for allowing one part of the information recording mediumto diametrically face at least one shell of the upper and lower shellsof the cartridge casing; and a central opening part for driving theinformation recording medium, the inner rotor being rotated in onedirection to drive the shutter and open the recording/reproducingopening part and the central opening part, wherein the shutter is drivenfrom a position where the recording/reproducing opening part and thecentral opening part are opened to a position where therecording/reproducing opening part and the central opening part areclosed by returning and rotating the inner rotor to the other directionby an extension coil spring or a compression coil spring, wherein anengaging part at one end of the coil spring is engaged with a bossshaped spring engaging part protruding on the inner surface of thecartridge casing and an end part of the spring engaging part is providedwith an engaging part slip preventing flange part for preventing theengaging part at one end of the engaged coil spring from slipping fromthe spring engaging part.
 8. A recording medium cartridge comprising: acartridge casing composed of upper and lower shells having aninformation recording medium, an inner rotor and a shutter accommodatedtherein, a recording/reproducing opening part for allowing one part ofthe information recording medium to diametrically face at least oneshell of the upper and lower shells of the cartridge casing; and acentral opening part for driving the information recording medium, theinner rotor being rotated in one direction to drive the shutter and openthe recording/reproducing opening part and the central opening part,wherein the shutter is driven from a position where therecording/reproducing opening part and the central opening part areopened to a position where the recording/reproducing opening part andthe central opening part are closed by returning and rotating the innerrotor to the other direction by an extension coil spring or acompression coil spring, wherein an engaging part at the other end ofthe coil spring is engaged with a hook shaped spring engaging partprovided in a coil spring attaching part of the inner rotor.